GEOMETRICAL, THERMAL AND MECHANICAL PROPERTIES OF OLIVE FRUITS MOHAMAD I. AL-WIDYAN 1,5 , TAHA M. RABABAH 2 , AHMAD MAYYAS 3 , MOH’D AL-SHBOOL 3 and W. YANG 4 1 Faculty of Engineering 2 Department of Nutrition and Food Technology 3 Industrial Engineering Department Jordan University of Science and Technology PO Box 3030, Irbid 22110, Jordan 4 Department of Food and Animal Sciences Alabama A&M University 4900 Meridian St. N., Normal, AL 35762 Accepted for Publication March 7, 2008 ABSTRACT In Mediterranean countries, olive trees play a significant economical role. Knowledge of olive fruits properties is essential for the efficient handling of the product and optimizing oil yield. The lack of such knowledge at the local level triggered this study in an attempt to report the fruit’s chemical compo- sition and some major engineering properties. Established procedures were followed in conducting the measurements and calculations on fruit samples. The study examined four major varieties of olive fruits, including Spanish, Black Spanish, improved Nabali and Nabali Baladi for their chemical com- position and other properties, including geometrical, thermal and frictional properties. Thermal properties, including thermal conductivity, heat capacity and thermal diffusivity, ranged from 0.41 to 0.47 W/(m·K), 2.35 to 2.39 kJ/ (kg·K) and 2.88 ¥ 10 -7 to 2.779 ¥ 10 -7 m 2 /s, respectively. The geometrical properties of the Spanish and Black Spanish were quite similar except for roundness and sphericity. Similar results were found for improved Nabali and Nabali Baladi. The properties of weight, density and packing coefficient ranged from 2.22 to 8.60 g, 890 to 1,230 kg/m 3 and 0.43 to 0.52, respectively. The fruit’s static friction coefficient over mild steel, aluminum and softwood surfaces ranged from 0.20 to 0.30, 0.21 to 0.29 and 0.22 to 0.33, respectively. 5 Corresponding author. TEL: +96227201000, ext. 22225; FAX: +962777284175; EMAIL: widyan@ just.edu.jo, trababah@just.edu.jo Journal of Food Process Engineering 33 (2010) 257–271. All Rights Reserved. © Copyright the Authors Journal Compilation © 2009 Wiley Periodicals, Inc. DOI: 10.1111/j.1745-4530.2008.00273.x 257